performance.getEntriesByType() - Web APIs 编辑

The getEntriesByType() method returns a list of PerformanceEntry objects for a given type. The list's members (entries) can be created by making performance marks or measures (for example by calling the mark() method) at explicit points in time.

Note:

Syntax

entries = window.performance.getEntriesByType(type);

Arguments

type

The type of entry to retrieve such as "mark". The valid entry types are listed in PerformanceEntry.entryType.

Return value

entries

A list of PerformanceEntry objects that have the specified type. The items will be in chronological order based on the entries' startTime. If no objects have the specified type, or no argument is provided, an empty list is returned.

Example

function usePerformanceEntryMethods() {
  log("PerformanceEntry tests ...");

  if (performance.mark === undefined) {
    log("... performance.mark Not supported");
    return;
  }

  // Create some performance entries via the mark() method
  performance.mark("Begin");
  doWork(50000);
  performance.mark("End");
  performance.mark("Begin");
  doWork(100000);
  performance.mark("End");
  doWork(200000);
  performance.mark("End");

  // Use getEntries() to iterate through the each entry
  var p = performance.getEntries();
  for (var i=0; i < p.length; i++) {
    log("Entry[" + i + "]");
    checkPerformanceEntry(p[i]);
  }

  // Use getEntries(name, entryType) to get specific entries
  p = performance.getEntries({name : "Begin", entryType: "mark"});
  for (var i=0; i < p.length; i++) {
    log("Begin[" + i + "]");
    checkPerformanceEntry(p[i]);
  }

  // Use getEntriesByType() to get all "mark" entries
  p = performance.getEntriesByType("mark");
  for (var i=0; i < p.length; i++) {
    log ("Mark only entry[" + i + "]: name = " + p[i].name +
         "; startTime = " + p[i].startTime +
         "; duration  = " + p[i].duration);
  }

  // Use getEntriesByName() to get all "mark" entries named "Begin"
  p = performance.getEntriesByName("Begin", "mark");
  for (var i=0; i < p.length; i++) {
    log ("Mark and Begin entry[" + i + "]: name = " + p[i].name +
         "; startTime = " + p[i].startTime +
         "; duration  = " + p[i].duration);
  }
}

Specifications

Browser compatibility

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